• Journal of Korean Society of societal Security
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• v.1 no.4
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• pp.73-81
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• 2008

Electromagnetic induction surveys are one of the useful methods to detect the location and buried depth of underground utilities by measuring horizontal and vertical magnetic fields. It can effectively detects single buried utility with the accuracy of within 20 cm. However when another utility is buried near to target one, the accuracy of utility location considerably decreases due to the distortion of magnetic fields caused from adjacent utility. This study shows the ways to verify the location and buried depth of target utility when magnetic fields does not show symmetric distribution due to adjacent another utility. Using Bluetooth wireless communication tools, we developed the way to records measured magnetic fields to handheld PDA. We investigated the criteria for minimum distance of two adjacent utilities to separate the individual responses through field model test.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.3
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• pp.3-10
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• 2007

As information communication technology matures, GIS is being evolved from wire communication GIS to mobile GIS. This is due that mobile GIS satisfy mobility, field work, speed and time. Also, this is proper that mobile GIS accomplish investigation, confirmation, input and modification operations of spatial and attribute data at field. I think mobile GIS's use is the best way. Because, Mobile GIS's use can accomplish effectively the management of various kinds facilities in city. On this study, we consider diversified methods a person in charge can management point and line data with more easy and more effective method. The management methods of pint type data are free method, offset method two point method. The management methods of line type data are free method, point connection method, point and line connection method and the minimum distance connection method between point and line.

• Nuclear Engineering and Technology
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• v.47 no.6
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• pp.729-737
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• 2015

Wireless communication technologies, especially smartphones, have become increasingly common. Wireless technology is widely used in general industry and this trend is also expected to grow with the development of wireless technology. However, wireless technology is not currently applied in any domestic operating nuclear power plants (NPPs) because of the highest priority of the safety policy. Wireless technology is required in operating NPPs, however, in order to improve the emergency responses and work efficiency of the operators and maintenance personnel during its operation. The wired telephone network in domestic NPPs can be simply connected to a wireless local area network to use wireless devices. This design change can improve the ability of the operators and personnel to respond to an emergency situation by using important equipment for a safe shutdown. IEEE 802.11 smartphones (Wi-Fi standard), Internet Protocol (IP) phones, personal digital assistant (PDA) for field work, notebooks used with web cameras, and remote site monitoring tablet PCs for on-site testing may be considered as wireless devices that can be used in domestic operating NPPs. Despite its advantages, wireless technology has only been used during the overhaul period in Korean NPPs due to the electromagnetic influence of sensitive equipment and cyber security problems. This paper presents the electromagnetic verification results from major sensitive equipment after using wireless devices in domestic operating NPPs. It also provides a solution for electromagnetic interference/radio frequency interference (EMI/RFI) from portable and fixed wireless devices with a Wi-Fi communication environment within domestic NPPs.

• Journal of Korea Technology Innovation Society
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• v.7 no.1
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• pp.89-110
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• 2004

Home networks consist of two or more home appliances or communication devices enabling the mutual data communication between appliances such as personal computers, refrigerators, phones, television sets, personal digital assistants(PDA), etc. There are three factors that create demand for the home network services. The first factor is development of technology. Second, on the demand side, consumer demand for the home appliances having access to the Internet is in the increase. Finally, producers need a strategy to deal with the problem of market saturation. Home networks are emerging markets. They are unique in that they unite information technologies with home appliances that provide new services. in this paper we study the main attributes of home network services and analyze consumers' preferences for them. However, it is not quite possible to use the revealed preference approach since the home network market is still at an incipient stage. We therefore use the conjoint analysis method using stated preference data. conjoint analysis has been widely use in the area of marketing for evaluating consumer preferences for new products and services. it presents a hypothetical product to the respondents along with the product's attributes and their levels. The respondents are asked to either rank each alternative or choose between several hypothetical products. By estimating consumers' willingness to pay for the attributes of the home network services and analyzing consumers' preferences, we predict the pattern of the development of the home network services and related technologies along various quality dimensions. Based on the estimation results, we draw policy implications for the national- and company-level strategy.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.324-327
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• 2006

The person who gets a ALS(Amyotrophic Lateral Sclerosis) has language disability and physical disability together. A common first symptom is a painless weakness in a hand, foot, arm or leg, which occurs in more than half of all cases. Other early symptoms include muscle weakness of speech. In the early stage of this disease they can communicate with other persons, but it will become increasingly difficult. In our research we have designed and implemented communication tools for them. We have implemented Chunjiin(the Korean computer keyboard) at PDA(personal digital assistant). And we have also implemented software which is consisted of frequently used words.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.433-441
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• 2007

The bio-Sensors, which are sensing the vital signs of human bodies, are largely used by the medical equipment. Recently, the sensor network technology, which composes of the sensor interface for small-seize hardware, processor, the wireless communication module and battery in small sized hardware, has been extended to the area of bio-senor network systems due to the advances of the MEMS technology. In this paper we have suggested a design and implementation of a health care information system(called u-EMS) using a bio-sensor network technology that is a combination of the bio-sensor and the sensor network technology. In proposed system, we have used the following vital body sensors such as EKG sensor, the blood pressure sensor, the heart rate sensor, the pulse oximeter sensor and the glucose sensor. We have collected various vital sign data through the sensor network module and processed the data to implement a health care measurement system. Such measured data can be displayed by the wireless terminal(PDA, Cell phone) and the digital-frame display device. Finally, we have conducted a series of tests which considered both patient's vital sign and context-awared information in order to improve the effectiveness of the u-EMS.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.93-102
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• 2010

Existing web based information service system solutions show limitations in mobile information services, as well as problems such as uncertain error messages, and difficulty providing swift assistance or real time emergency support. In order to solve these deficiencies, a realtime wireless remote control system has been designed and implemented in this thesis, which is capable of managing and monitoring remote systems using mobile communication devices (Mobile Phone, PDA, Smart Phone) for realtime control. Proposed systems are applied at remote places, for instance 'office building', and a nursery school like 'kindergarten'. In the case of implemented at office building, it can be managing and controlling at real time all sorts of the sensor information that are installed at office building system environment through wire(web environment) or wireless(mobile device). In the other case at kindergarten system that are providing the real-time wireless remote control and monitoring system can be monitoring activity of kindergarten children with a mobile phone of authentication user. The security functions of proposed systems include mobile device user authentication and target system access control. The proposed systems allow real-time user authentication function and system access control function that improve the security of resource administrators and mobile device users, and provides not only uninterrupted services, but also real time mobile service environments.

• Journal of KIISE:Databases
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• v.33 no.3
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• pp.299-309
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• 2006

Due to the rapid development in mobile communication technologies, the usage of mobile devices such as cell phone or PDA becomes increasingly popular. As different devices require different applications, various new services are being developed to satisfy the needs. One of the popular services under heavy demand is the Location-based Service (LBS) that exploits the spatial information of moving objects per temporal changes. In order to support LBS efficiently, it is necessary to be able to index and query well a large amount of spatio-temporal information of moving objects. Therefore, in this paper, we investigate how such location information of moving objects can be efficiently stored and indexed. In particular, we propose a novel location encoding method based on hierarchical administrative district information. Our proposal is different from conventional approaches where moving objects are often expressed as geometric points in two dimensional space, (x,y). Instead, in ours, moving objects are encoded as one dimensional points by both administrative district as well as road information. Our method is especially useful for monitoring traffic situation or tracing location of moving objects through approximate spatial queries.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.240-249
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• 2001

A high speed ultra-compact lens with a diffractive optical element (DOE) is designed, which can be applied to mobile communication devices such as IMT2000, PDA, notebook computer, etc. The designed hybrid lens has sufficiently high performance of less than f/2.2, compact size of 3.3 mm (1st surf. to image), and wide field angle of more than 30 deg. compared with the specifications of a single lens. By proper choice of the aspheric and DOE surface which has very large negative dispersion, we can correct chromatic and high order aberrations through the optimization technique. From Seidel third order aberration theory and Sweatt modeling, the initial data and surface configurations, that is, the combination condition of the DOE and the aspherical surface are obtained. However, due to the consideration of diffraction efficiency of a DOE, we can choose only four cases as the optimization input, and present the best solution after evaluating and comparing those four cases. On the other hand, we also report dramatic improvement in optical performance by inserting another refractive lens (so-called, field flattener), that keeps the refractive power of an original DOE lens and makes the petzval sum zero in the original DOE lens system. ystem.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.4
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• pp.22-31
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• 2008

Recently, with the develop of the location tracking technology using GPS and mobile device such as PDA and UMPC, it is used in various application fields that is coordinate transformation and compensation using GPS, is client development for Mobile GIS using GIS and is development of surface survey system for archaeological site based on mobile. In this paper, we develop the system that can investigate the growth information and production information of rice in crop of the field using mobile device, show position information of user and rice in digital map using GIS and save the investigated crop information and position information in database in server. The system which is developed in this paper consists of modules that the user management module is able to restrict database approaches in authority by of the user, the crops management module is able to save and search crop information in database in server, the map module is able to show position information of user and crops in digital map, the location information module is able to convert received location information from GPS and the communication module is able to send and receive data between GPS and mobile device and between mobile device and database. Finally, this paper shall contribute to efficient management and investigation of birth information of crop in field.